Electrooptical testing device for timepieces



Sept. 22, 1936. A. DISTELI 2,055,231

ELECTROOPTICAL TESTING'DEVICE FOR TIMEPIECES Filed Feb. 10, 1933 /II/I/I/Il/II'II '/////I///////////////////II//II/I/l OSCILLQ GEA PH I /um 1.0 7. 52.

ATTORNEY UNITED STATES PATENT OFFICE ELECTROOPTICAL TESTING DEVICE FOR TIMEPIECES Alfred Disteli, Olten, Switzerland, assignor to Ernst Leitz Optische Wei-kc, G. in. b. 11., Wetzlar, Germany "Application February 10,1933, Serial No. 656,102 Km Switzerland March29, 1932 ll Claim. (Cl. 7H1) This invention relates to improvements in traces a curve which can more readily be obtesting devices, particularlyto an electro-optical served. device for testing the working of clock-works or The mirror F makes approximately three revosimilar escapement controlled works in which lutions for each tick of the timepiece so that for the beats of the.- escapement are microphonically each swing of the mirror D a curve is described liregistered and transformed into electrical oscilon the screen G, these successive curves being lations in an intensifier which are then used to superimposed one upon the other.

operate an electric oscillograph for recording the According to the present invention the rotary oscillations by optical means by means of a light mirror F is driven by means which can be adray upon a screen. In order to record such short justed so as to drive the mirror at any desired w oscillations in their rapid succession, it is necesconstant speed. In the construction shown an sary to let them appear in their optical reproducelectric motor (not shown) transmits the drive tion in a multiple repetition on a screen so as through gearing H, arranged within a casing H to enable a correct observation of the same. For to a shaft H carrying a friction disc H which this purpose in many instances rapidly operating bears against a disc F carried by the shaft of the M15 revolving mirrors are used which will reproduce mirror An adjustable governor J driven by or reflect the rays on the screen in multiple. the shaft H is empl y to regulate h Speed It is the object of my invention to make use of of the mirror F as by applying a brake to the such a revolving mirror, and to drive the same driven mechanism or by adjusting the field circuit by means of a regulative drive equipped with an of the driving motor which may be arranged 20 adjustable governor and the drive is so constructeither inside or outside the casing H The ed as to keep constant by means of the governor governor J, after initial setting, maintains the a certain predetermined speed after it has been speed of rotation of the mirror F at a constant once adjusted to a speed commensurate to the value.

speed required to the production of a constant The apparatus according to the invention is 25 and accurate curve on the screen. Thus any demore especially intended for testing a watch. viation of the curves from the constant curve on clock or other time indicator having escapement the screen towards one or the other side during mechanism, by comparison with a previously regthe operation will. indicate any irregularities in ulated standard movement. To this end the u the working of the clock or other work. standard movement is first placed on or adjacent In the accompanying drawing forming a mateto the microphone B and the speed of the motor rial part of this disclosure: H is adjusted until the curve traced by the light The single figure is a diagrammatic view of a beam on the screen (3- remains stationary, that device constructed according to my invention. is to say so that each successive curve traced on In the arrangement illustrated the ticks of a the screen is exactly superposed upon the pre- 35 timepiece such for example as a watch or clock ceding curve. The speed of the disc F and A are transmitted from a microphone B and electherefore the rotary mirror F are now maintained trically amplified by an amplifier C. The elecconstant and the curve obtained from the standtric oscillations produced actuate an oscillograph and movement is removed and replaced by the comprising an oscillating mirror D and an excitatimepiece to be tested. If the frequency of the tioncoil D a light source E directing a beam E ticks of this timepiece exactly synchronises with on to the mirror D which deflects the light as that of the standard movement the curve traced shown at E The beam E is thus swung to and by the light beam projected on to the screen 1:0 in accordance with the ticks of the time- G will remain stationary relatively to the curve piece A. a produced from the standard movement.

Thoughthe beam E could be thrown directly If however the frequency of the ticks of the on a screen and the resulting path traced by the timepiece to be tested is faster or slower than moving spot of light examined, the Oscillation that of the standardmovement the resulting curve of the beam would in practice be too rapid to traced by the light beam on the screen G will to permit accurate observation, by the naked eye. move or vary in one direction or the other rela- 5 The beam E is therefore deflected by a fourtively to the curve produced from the standard faced mirror F rotated about a horizontal axis movement. The speed of the timepiece to be so that each face in turn throws the beam E tested can thus'be accurately compared with the on to a screen G whereby instead of tracing a standard movement, the curve traced by the light 66 substantially straight line on the screen the beam beam clearly indicating whether the timepiece :illograph, a microiying the osci1la-' used by. the beats l of the time-piece i and its mirror, a '5 upon said mirror, iree times about its iement mechanism Ihich the rays diirror are deflected, re representing the nism of a standard deflected by said reen in a multiple -n said screen, the be standard curve regularities in the re tested. and mei revolving mirror revolutions.

"'RED DISTELI.

viding means for accurately synchronising or,

comparing the frequency of two timepieces the curve traced by the light beam produced from any single timepiece will indicate clearly whether or not the timepiece under test is operating regularly or otherwise. Y

It will be understood that I have disclosed the preferred form of my device only, and that I may make such changes therein as come within the scope of the appended claim without departure from the spirit of my invention and the principles involved. 7

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

In an electro-optical testing. device for timepieces, including an electro-osc phone, an intensifier intensi tions of said microphone cm of the escapement mechanism for operating said oscillograpl source of light directing its ray a revolving mirror revolving th axis at each beat of the esca of the time-piece andupon v rected upon the oscillograph m and a screen upon which a cum beats of the escapement mecha time piece is marked, the ray: revolving mirror upon said so: repetition to project a curve 0 deviation of this curve from t. on the screen indicating any i1 working of the time-piece to t chanical means to revolve salt and controlling the speed of its ALF 

